Electric switch



June 5, 192s. I

. G- A. BURNHAM 1672365 ELECTRIC SWITCH File July 25. 1921 fra ven or Patented June 5, 1928.

UNITED STATES PATENT OFFICE.

GEORGE A. BUR-NHAM, OF SAUGUS, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO CONDIT ELECTRICAL IvIANUFACTURING CORPORATION, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

ELECTRIC SWITCH.

Application y filed July 25,

.This invention relates to oil immersed electric switches of 'Y the type characterized by having a relatively yieldingly connected or supported oil receptacle and switch frame; and as set forth in my co-pending application Serial No. 309,853, iiled July 10,1919. which application has eventuated in Patent No. 1,413,156, dated April 18, 1922.

For certain purposes it is preferable to employ a lixed switch trame and a yieldingly-supported movable oil receptacle; and such a type is illustrated in said co-pending application; and for other purposes it is 5 preferableto employ a fixed oil receptacle and a movable switch frame yieldingly disposed with relation to the oil receptacle: and such a. switch is typified in a removable-unit cell-type switch.

yThe current carried by a switch of the latter type may be considerable and the circuit leads or bus bars to which the stationary switch-members are adapted to be connected are relatively massive and rigid members and, furthermore, are rigidlysupported by xed insulators secured to stationary supports.` The stationary7 switch members are carried by the yieldingly-supported movable frame and consequently have a movement relativeto the rigidlysupported circuit leads or bus-bars. lith thel usual type of connection between the switch-members andfcircuit leads or busbars, both are rigidly united, with the result that either the bus-bars may restrain the framel from yielding to relieve the strain on the switch due to a gaseous pressure rise within the switch resulting from interrupting the circuit under load, or the bus-bars may be torn from their supports when the circuit is interrupted and the switch frame is moved upward against its yielding supporting-means.

An object of this invention is to provide the combination of an electric-switch having ya yieldingly-supported movable switch frame bearing the stationary switch-members, stationarily-secured rigid bus-bars and iiexible means yieldingly connecting' said switch-members and bus-bars *electrically whereby to absorb the movement ot said switch-members and permit a movement of 1921. Serial No. 487,221.

said switch trame and switch-members independently of said bus-bars.

A further object is generally to improve the construction and operation of an electric switch.

Fig. 1 is a side elevation of a removable unit2 cell-type switch selected to illustrate the invention.

Fig. 2 is a sectional detail of the switch of Fig. 1 with the switch frame in a vertically displaced position and illustrating the manner in which the iiexible connectors absorb the movement of the switch-'members without transmit-ting the movement to the stationarily-supported bus-bars.

Fig. 3 is a diagrammatic detail illustrating the invention applied to the combination of the switch of Fig. 1 and horizonally-arranged7 stationarily-supported busars.

Fig. 4 is a perspective vview of a flexible connector.

As here shown, the switch embodying the invention is disposed in a cell A. The switch comprises the fixed oil receptacle 10 mounted on the carriage 11 by which the switch, when disconnectedfrom the stationarily-supported bus-bars may be moved as a unit from the cell. A trame 12, compris-- ing a cover tor the oil receptacle, is disposed over the top of the oil receptacle and is yieldingly secured thereon by the bolts 13 carried by the oil receptacle and the helical springs 14 disposed over said bolts and engaging lugs 15 of said frame. Said frame may be removed from the oil receptacle by lirst removing the nuts 16 threaded removably on the ends of said bolts; and the tension of said springs, and, therefore, the movement. of said trame, may be governed b v an obvious adjustment of said bolts. The switch may be vented downwardly through. the peripheral passage 17 between the tlange'12a of the switch frame and the side wall of the oil receptacle.

Due to the Aopening ofthe switch under load av considerable gaseous pressure may be created in the kexpansion space B above the oil in the oil receptacle and under the switch trame, vand said switch frame will be Amoved upwardly against the springs 14- by said pressure to increase the volume of said expansion space and keep down the internalpressure and reduce stresses on the bolts 13 while the pressure is being relieved by aidischarge of gas and vapor through the vent passage 17.

A movable switch member 20 is disposed within said oil receptacle and is dependingly secured-to switch-operating mechanism 2l, here shown as carried by said switch trame although it may be supported otherwise in any desirable manner. Stationary switchmembers 22 are secured rigidly to the switch frame and are movable therewith yresponse to pressure conditions within .the switch. A

In the cell-type switch illustrated in Fig. 1 the rigid circuit leads or bus-bars 23 are secured -immovahly in insulators 24 carried by .the stationary top wall 18 of the cell A.

With a fixed or stationarily-supported.sw-itch frame the connectors extended between `said lbus-bars and the stationary switch members are rigid and inflexible members. In accordance with the invention, l employ flexible means to Vconnect said bus-bars and switch-members electrically whereby to admit of the vertical movementV of said switch frame relative to said bus-bars in response to pressure conditions within Athe switch.

ISaid flexible means maycomprise the flexible connectors .25; .and said connectors may each comprise one or a plurality of flexible strips 26 united iat .their ends by suitable means, as by solder, but otherwise .preferably unconnected, Aat least for the major portion of their length, whereby each. strip may flex and bend .and absorb the motion of said switch frame and stationary switch members independently .of other strips of the connector. Each strip may be spaced from adjacent strips by the lspacer blocks 27 and 28 if desired, to enhance Athe freedom of movement of each striip; and said spacer blocks may ,also serve to fprovide relatively massive terminals for the connector. The number of strips may. vary, as may also the dimensions of the strips, 4but preferably the strips are relatively thin,for flexibility and broad wherebv to radiate heat the more effectively. The terminals of i said connectors may be provided with bolt-holes 29 and said connectors may be ,secured removably to said bus-bars and stationary switch-members by the bolts 30. The length of said con` nectors is preferably substantially .greater than the distance between theA stationarilysupported bus-bars and stationary switchmembers in the normal, which will be the lowest, position of Athel switch frame; and the flexible connectors will thereby assume Va sinuous shape, as illustrated, whereby to enhance the flexibility of the connectors.

It will be appa-rent. that, with the construction above s'et forth, the switch Jframe i and 'stationary lswitch-menib'ers may move upward in response to pressure conditions within the switch, and return to normal position without putting strain on, or tendency to move, the stationarily-supported bus-bars, and the movement of the switch frame and switch-members will be absorbed in the flexible connectors.

When the switch is to be removed 'from the cell the flexible connectors will be rst detached from` the stationary switch-members by removing the connecting bolts 30.

In Fig. 3 'the sta'tionarily-supported rigid bus-bars 23L are horizontally-arranged instead of vertically-arranged as `in Fig. 1, and arev stationarily-supported on rthe rigidly fixed insulators 24a above the switch frame and are connected to the switch-members 22 by the llexible connectors. 25 'as in f movement. of the switch-members.

The vswitch operating mechanism 21 is here shown as carried lby the movable switch frame 12 and operated by theelectricallycontrolled lmechanism 35 'disposed upon the top wall 18 of the cell by the verticallymovable krod 36 which is connected removably to the operating mechanism by the bolts t 37. VWhen the switch is to be removed from the cell the rod 36 will he disconnected from the operating mechanism by removing the bolts 3'? as is usual practice with thisltyp'e Vof switch.

The switch 'operating mechanism specilically includes the lever 21"GL pivoted at one end to the switch frame 12 and bearing the movable switch-member 20 at the other end. A lever 2lb is also pivot'ed to sai-d switch frame and is loosely connected to the lrod i 21; and said rod is connected `to the rod 36 f of the electrically-controlled mechanism '35.

A link 21d is pivotally connected with said lever 2la and said lever 21". Said mechani'sm is so arranged that an upward movement of said rod 21c operates to move said movable switch-member 20 upwardly to close the switch, and a downward movement of said rod operates to open ythe switch. It will be noted that, as the switch-'operswitch frame and the rod 2lC thereof is Aconnected to the stationarily-supported electrically-controlled mechanism '35, when `said switch frame is moved upward in response to pressure conditions within 4the switch due to the `separation vof the stationary and movable switch-members, it will operate on 'the vating 'mechanism is carried by the movable Y switch-operating mechanism to move the movable switch-member 20 toward open position and accelerate thev switch-opemng movement thereby to provide for a more rapid interruption of the circuit and thereby reduce the gaseous pressure rise and increase the interrupting capacity of the switch than would otherwise be the case.

The invention may be embodied in other combinations than herein set forth without departing from the spirit thereof.

I claim:

l. An electric switch having a stationary oil receptacle, a switch frame comprising a cover for said oil receptacle movable thereon in response to pressure conditions within the switch, stationary and movable switch members immersed in the oil lin said oil receptacle, switch operating mechanism connected with the movable switch member and cover, and means havin a connection with said operating mechanlsm whereby the upward of opening movement of the movable switchmember.

2. An electric switch having means to accelerate the opening movement of the switch comprising the combination of a stationary oil receptacle, a switch-frame comprising a cover for said receptacle movable thereon in response to pressure conditions within the switch, stationary switch-members carried by said frame, a movable switch-member and switch-operating mechanism carried by said frame, stationarily-supported controllingmechanism for said operating mechanism, and an operating rod extended between and connecting said controlling and operating mechanisms.

Intest-imony whereof, I have signed my name to this specification.

GEORGE A. BURN HAM. 

